1. Field of the Invention
The present invention relates to a storage apparatus and a storage method and, more particularly, to a storage apparatus and a storage method suitable for, for example, use for enlarging an image.
2. Description of the Related Art
A coding method is known in which high-resolution image data is set as most basic layer or first layer image data, second layer image data of a smaller number of pixels is formed, and third level image data of a further smaller number of pixels is formed, followed by formation of fourth to uppermost layer image data. Such coding is called hierarchical coding, and image data in each layer is displayed on a monitor having a resolution (number of pixels) corresponding to the layer. Accordingly, a user can select image data in hierarchically encoded image data corresponding to the resolution of a user's monitor to view corresponding images.
In the conventional hierarchical coding, however, original image data is set as first layer image data and only image data in high layers relating to smaller numbers of pixels is formed. That is, by the conventional hierarchical coding, no image is formed of a number of pixels larger than the number of pixels of original image data.
In hierarchical coding, it is convenient to use a method of forming an image of a number of pixels larger than the number of pixels of original image data (hereinafter referred to as pixel-multiplied image as occasion demands) when, for example, electronic zooming is performed.
That is, if an image of a number of pixels smaller than the number of pixels of original image data is prepared, the image can be immediately reduced in size, and, if a pixel-multiplied image is prepared, the image can be immediately increased in size.
In general, in electronic zooming, the image enlarging function is used more frequently than the image reducing function. That is, in a case where a user is viewing, for example, an image transmitted or reproduced from a recording medium, it is quite possible that he or she wants to enlarge a part or the entirety of the viewed image.